Router jig for forming corners on decorative molding

ABSTRACT

The router jig of this invention uses a preformed negative form of the decorative molding as a guide which directs a router having a straight router bit along the end of a piece of the molding to appropriately form the end for an inside corner. The router jig includes a generally rectangular frame having a router support tray which is slidable relative to the frame. A slot is formed through one side wall of frame. A biased guide pin is connected to the router support tray and is accommodated within the slot of the frame. In use, a router is placed onto the router base and in contact with the guide pin which is extending through the slot. The opposite end of the guide pin is placed in contact with the negative form. With a piece of molding clamped under the frame, the router is turned on and slid with the router base perpendicularly across the molding. As the router is slid relative to the frame and molding, the guide pin is guided along the negative form. Contact between the negative form, the guide pin and the router causes the router to follow the path of the negative form and route a similar profile onto the end of the piece of molding.

FIELD OF THE INVENTION

[0001] This invention relates to a router jig as used in woodworking andhas specific relevance to a router jig used to form inside corners withdecorative molding used in construction specifically as base molding orcrown molding.

SUMMARY OF THE INVENTION

[0002] Decorative molding is used in the construction industry as finishtrim on a wall adjacent the either the floor and ceiling or between thefloor and ceiling as a “chair rail”. Decorative molding placed adjacentthe floor is typically referred to as “base molding” and decorativemolding placed adjacent the ceiling is typically referred to as “crownmolding”. Typically the decorative molding has an irregular crosssection including a series of ribs and concavities which form anaesthetically pleasing design. To attach the molding to the wall at aninside corner of a room, the carpenter is required to hand carve or usea coping saw to form an end of the molding such that it mates againstthe molding on the perpendicular wall. Merely cutting the molding at a45 degree angle would not form a clean corner due to the irregular crosssection of most decorative molding. Typically, this requires thecarpenter to trace the profile of the molding onto the end of themolding to be cut and repeatedly test fit the piece against the moldingalready extending into the corner. In a large house with a substantialamount of molding, or when fitting an intricate molding, this processcan significantly increase the amount of time required to fully trim outa house with decorative molding.

[0003] The router jig of this invention eliminates the problemsexperienced with hand carving decorative molding for corners andsignificantly reduces the time involved by using a router to carve anend on decorative molding to fit within a corner. The router jig uses apreformed negative form of the decorative molding as a guide whichdirects a router having a straight router bit along the end of a pieceof the molding. The router jig includes a generally rectangular framehaving a router support tray which is slidable relative to the frame. Aslot is formed through one side wall of frame. A biased guide pin isconnected to the router support tray and is accommodated within the slotof the frame. In use, a router is placed onto the router base and incontact with the guide pin which is extending through the slot. Theopposite end of the guide pin is placed in contact with the negativeform. With a piece of molding clamped under the frame, the router isturned on and slid with the router base perpendicularly across themolding. As the router is slid relative to the frame and molding, theguide pin is guided along the negative form. Contact between thenegative form, the guide pin and the router causes the router to followthe path of the negative form and route a similar profile onto the endof the piece of molding. In this manner, one pass with a router is allthat is required to form an appropriate end on the decorative moldingfor fitting within an inside corner of a room. Therefore, once therouter jig of the invention is initially set up, only a few seconds arerequired to form the molding end appropriately thereby savingsubstantial time over the prior art hand carved method. The reduction oftime required for a carpenter to trim out a house should translate intosavings to the home owner.

[0004] Accordingly, it is an object of this invention to provide for anovel router jig to route an end of decorative molding for fittingperpendicularly against a second piece of the molding at an insidecorner.

[0005] Another object of the invention is to provide for a novel routerjig wherein the router follows a guide pin in contact with a negativeform of decorative molding so that the router reproduces the patternformed by the negative form on a piece of molding.

[0006] Still another object of the invention is to provide for a novelrouter jig that can be easily adapter to route ends on decorativemolding having a wide variety of cross sectional shapes.

[0007] Other objects of the invention will become apparent upon areading of the following description taken along with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008]FIG. 1 is a perspective view of the router jig of this inventionwith a router illustrated in broken lines to illustrate the environment.

[0009]FIGS. 2 through 4 are elevational views of the router jig of theinvention in use and illustrating the setup of the jig and the routingof a piece of molding.

[0010]FIG. 5 is a cross sectional view taken along line 5-5 of FIG. 3.

[0011]FIG. 6 is a cross sectional view taken along line 6-6 of FIG. 3.

[0012]FIGS. 7 and 8 illustrate decorative molding routed using the jigof this invention forming an inside corner.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0013] The preferred embodiment herein described is not intended to beexhaustive or to limit the application of the invention hereindisclosed. Rather, it is intended merely to fully explain the inventionso that others skilled in the art might utilize the teachings containedherein.

[0014] Initially, to provide a clearer understanding of the particularpieces of molding required to form an inside corner and to therebyenable the explanation of the invention, reference is made to FIGS. 7and 8. FIGS. 7 and 8 illustrate two pieces of a decorative moldingshaped to form an inside corner. Specifically, molding piece 1 and 2 areillustrated. It should be noted that pieces 1 and 2 have substantiallysimilar cross sections. Each piece 1 and 2 has a flat side “F” intendedto be placed adjacent the supporting wall (not shown). Further eachpiece includes a decorative side “D” on an opposite side of side F.Therefore, side D is intended to face into the room and provide theaesthetically pleasing appearance. Each piece 1 and 2 also includes aflat bottom side which is substantially perpendicular to side F. Moldingpiece 2 terminates in a blunt end substantially perpendicular to side Fand as illustrated in FIG. 7, molding piece 1 has been shaped by theinvention to terminate in an irregular end “I”. As illustrated best inFIG. 8, irregular end I of molding piece 1 is intended to be positionedagainst side D of molding piece 2, therefore, the irregular end I hasbeen formed by the router jig of this invention to be a substantialnegative image of side D. Further, as best illustrated by FIG. 8, theirregular end I has been formed with a small included angle A. As onlyside D of the molding pieces will be seen by the home owner, forming theirregular end with the small included angle A will assist the carpenterin forming the inside corner in the event that the walls (not shown) donot meet at an exact 90 degrees.

[0015] With the above descriptions and definitions in mind, attention isnow directed to FIGS. 1-6 which illustrates the router jig 10 of theinvention used to form irregular end I on molding piece 1. Router jig 10includes a generally rectangular and hollow frame 12 having a slot 13formed through one side thereof. Frame 12 is secured to a base 9 formedfrom wood by screws (not shown). Base 9 include a large generallyrectangular hole 11 formed therethrough as illustrated. A router supporttray 14 is carried within frame 12 and slides relative to the basewithin tracks 16 formed in the interior side walls of frame 12. Routersupport tray 14 includes a plate portion 18 having a generallyrectangular opening 20 therethrough and upturned front and back edges 22and side edges 23. Preferably, router support tray 14 is formed suchthat a router 8 (shown in broken lines in FIG. 1) fits between edges 20without substantial play. However, as will be explained later, therouter support tray and frame should be wide enough to permit the routerto slide in the direction of arrow 7 between side edges 23. Finally,router support tray 14 includes a guide pin 24 which extends through ahole (not shown) in one side edge 23 and through slot 13 in the frame.Pin 24 is biased toward the interior of router support tray 14 by ahelical spring 26. Pin 24 terminates in a blunted end.

[0016] A pair of temporary guides blocks 27 are connected to base 9 byscrews (not shown) and are spaced relative to one another a distancesufficient to snugly accommodate molding piece 1 in the orientationillustrated in the figures. An additional hold down clamp 28 may beconnected to one or more of the guide blocks 27 to assist in temporarilyfixing the molding piece 1 to the router jig 10 for forming irregularend I.

[0017] Finally, a negative form 30 is connected by screws 32 to theguide blocks 27 adjacent slot 13 and the frame side wall. Negative form30 includes an interior surface 34 which is a negative image of thedecorative side D of molding piece 1. Negative form 30, and morespecifically, the interior surface of negative form 30 may be formed ina variety of methods. For example, the outline of decorative side D ofmolding piece 1 could be traced onto a block of wood. The carpentercould use a band saw or coping saw and cut along the trace line to formthe interior surface 34. However, it is preferred for proper operationof the router jig that the interior surface of the form be extendedbeyond the top and bottom edges of the actual molding width to provideroom for the guide pin and permit the router bit to start and finishpast the molding piece 1. Alternatively, a quantity of molding resincould be placed adjacent decorative side D of the molding piece andallowed to harden to form the interior surface 34.

[0018]FIGS. 2 through 6 of the included drawings illustrate the use ofthe router jig of the invention in the formation of the irregular side Ion molding piece 1. For clarity, the router will either not be shown orwill be shown in broken lines so that the operation of jig can be moreclearly illustrated.

[0019]FIG. 2 illustrates the position of the router support tray 14prior insertion of molding piece 1 into the router jig 10. It should benoted that the guide pin is out of alignment with the trough formed byblocks 27. Therefore, with a router carried by the support tray 14, anda straight bit in the router, the router bit would be out of contactwith the molding piece as the molding is slid into position.

[0020]FIGS. 3 and 6 illustrate the same router jig and molding piecewith the router beginning to route the irregular end I on the end ofmolding 1. Flat side F (not shown) is position against base 9 anddecorative side D is facing upward. Router support tray 14 with router 8(illustrated only by a broken circle in FIG. 3) is slid in the directionof arrow 6 with the router running and turning router bit 5. As the tray14 and router are slid in the direction of arrow 6, the carpentermaintains contact between the periphery of the router (illustrated bybroken circle 4 in FIG. 3), the guide pin 24 and the interior surface 34of negative form 30.

[0021]FIG. 4 illustrates a continuation of the sequence of FIG. 3,again, with the outer periphery of the router illustrated only by brokencircle 4. It should be noted that as the support tray 14 and router wereslid in the direction of arrow 6 from the position illustrated in FIG. 3to the position illustrated in FIG. 4 that the router was required toslide within support tray 14 in a direction perpendicular to arrow 6 asthe guide pin encountered the various irregular curves of the interiorsurface 34 of the negative form 30. Finally, it should be noted thatsince the negative form 30 is slightly larger than the actual moldingpiece 1, bit 5 was allowed to pass completely through the molding pieceto fully form irregular end I on molding piece 1. At this point, theirregular end I of molding piece 1 is completely formed and the user mayrelease clamp 28 and fit molding piece 1 against piece 2 to form acorner as illustrated in FIG. 9.

[0022] As mentioned earlier, it is preferred to form the irregular end Iof molding piece 1 with a small included angle to assist the carpenterin fitting the molding into a corner that may not be exactly 90 degrees.FIG. 5 illustrates the manner in which the small included angle isformed in irregular end I. Specifically, it can be seen in FIG. 5 thatthe tracks 16 formed in the longitudinal side edges of frame 12 areoffset relative to one another such that the router tray carried by theslots is positioned at a small angle relative to base 9. The axis of therouter 8 and bit 5 (represented by broken line 38) are, therefore,positioned at a small angle A relative to the vertical axis of therouter jig (represented by broken line 40). As the router bit 5 passesthrough molding 1 to form irregular end I, as explained above, theoffset between the vertical axis of the jig and the axis of the routerand bit is transferred to the end I (see FIG. 8).

[0023] It should be understood that the invention is not to be limitedto the precise details above, but rather may be modified within thescope of the appended claims.

I claim:
 1. A jig for guiding a powered router and router bit across apiece of wood to form an irregular end thereon, said jig including, aframe a router support tray carried by said frame, wherein said routersupport tray is slidable relative to said frame from a first positiontoward a second position, a guide pin carried by said router supporttray having one end configured for contact with a peripheral edge of apowered router, said guide pin extending through a slot in said frame,and a form connected adjacent to said frame in alignment with said slotsuch that a second end of said pin slidingly contacts in interiorsurface of the form.
 2. The jig of claim 1 wherein said frame includes apair of parallel channels on opposing side walls, said router supporttray being positioned within said channels and slidable within saidchannels relative to said frame.
 3. The jig of claim 1 wherein therouter support tray includes a central opening therein for accommodatinga router bit therethrough.
 4. The jig of claim 1 wherein the routersupport tray is generally rectangular.
 5. The jig of claim 1 whereinsaid guide pin carried by said router support tray is biased away fromsaid form.
 6. The jig of claim 2 wherein said pair of parallel channelsin said frame are offset from one another relative to a vertical axis ofsaid frame such that said router support plate is positioned at an anglerelative to the vertical axis of said frame.
 7. A jig for guiding apowered router and router bit across a piece of wood to form anirregular end thereon, said jig including, a frame having a pair ofparallel channels on opposing side walls, a generally rectangular routersupport tray having a central opening therein for accommodating a routerbit therethrough, said router support tray being carried by said frameand extending into and between said channels wherein said router supporttray is slidable within said channels relative to said frame from afirst position toward a second position, a guide pin carried by saidrouter support tray having one end configured for contact with aperipheral edge of a powered router, said guide pin extending through aslot in said frame, and a form connected adjacent to said frame inalignment with said slot such that a second end of said pin slidinglycontacts in interior surface of the form, wherein said guide pin carriedby said router support tray is biased away from said form.
 8. The jig ofclaim 7 wherein said pair of parallel channels in said frame are offsetfrom one another relative to a vertical axis of said frame such thatsaid router support plate is positioned at an angle relative to thevertical axis of said frame.
 9. A method of forming an irregular end ina piece of decorative molding for forming an inside corner with asimilar piece of decorative molding, said method including the steps of:forming a negative form of said decorative molding wherein said formincludes an interior surface which is a negative of an exterior surfaceof the decorative molding; providing a router frame providing a routersupport tray carried by said frame, wherein said router support tray isslidable relative to said frame from a first position toward a secondposition, providing a guide pin carried by said router support trayhaving one end configured for contact with a peripheral edge of apowered router, said guide pin extending through a slot in said frame,providing a negative form connected adjacent to said frame in alignmentwith said slot such that a second end of said pin slidingly contacts ininterior surface of the form, placing a router onto said router supporttray such that a router bit extends through a central opening in saidrouter support tray, placing a piece of decorative molding in saidrouter jig such that a portion of said molding is in alignment with saidrouter bit, said decorative molding having an exterior surfacesubstantially matching the interior surface of said negative form,rotating said router bit and sliding said router support tray and routerrelative to said frame from a first position spaced from a lateral edgeof said molding toward a second position on an opposite edge of saiddecorative molding, wherein as said router and support tray is slid in afirst direction from said first position toward said second position,said guide pin is positioned between the interior surface of thenegative form and a peripheral edge of the router, said guide pinfollows the interior surface of said negative form as said support trayand router are slid from the first position toward the second positionto cause said router to slide relative to said router support tray in asecond direction perpendicular to said first direction.